Hurwitz-stability conjecture for rising-factorial Toeplitz determinants

About 14 years old · traced to

Let {fk}k=0n\{f_k\}_{k=0}^{n} be a non-negative sequence, let α,β>0\alpha,\beta>0, and define

Qnα,β(x):=∑k=0nfkfn−k(nk)[(x+α)k(x+β)n−k−(x+α+β)k(x)n−k].Q^{\alpha,\beta}_n(x):=\sum_{k=0}^{n}f_kf_{n-k}\binom{n}{k}\left[(x+\alpha)_k(x+\beta)_{n-k}-(x+\alpha+\beta)_k(x)_{n-k}\right].

A real polynomial is Hurwitz stable when all its zeros have negative real part. The Hurwitz-stability conjecture. If fk2>fk−1fk+1f_k^2>f_{k-1}f_{k+1} for k=1,2,…,n−1k=1,2,\ldots,n-1 and n≥3n\geq3, then Qnα,β(x)Q^{\alpha,\beta}_n(x) is Hurwitz stable.

For real polynomials, Hurwitz stability implies positivity of coefficients, so this conjecture would imply the preceding coefficient-positivity conjecture. Its status is not resolved in the supplied source context.

References

Primary source

Dmitry Karp, “Positivity of Toeplitz determinants formed by rising factorial series and properties of related polynomials”, arXiv:1203.1482 (2012).

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.